So far, various proposals have been made of the technique according to which, while a photosensitive material having an electrode layer and a photoconductive layer stacked on a base or substrate in this order is opposed to an electrostatic information recording medium having an electrode layer and a charge carrier layer stacked on a base or substrate in this order, voltage is applied between both the electrodes to expose the recording medium to image-bearing light, thereby recording an electrostatic latent image in the charge carrier layer. This technique makes analog recording of very high resolution, and so provides an excellent electrostatic information recording method. However, a problem with this method is that the surface charges recorded on the surface of the charge carrier layer is likely to attenuate gradually due to atmospheric moisture, dust, and so on. Another problem is that the electrostatic latent image is destroyed upon something externally applied thereto or coming into contact therewith.
To solve such problems, it has been proposed to stack a protecting layer on the surface of the charge carrier layer after an electrostatic latent image is formed thereon. It has also been put forward to form a charge carrier layer by stacking a photoconductive or electrically conductive layer on an electrically insulating layer in a pixel unit pattern and stacking a thin film form of electrically insulating resin layer on the conductive layer, and allow an electrostatic latent image formed on the surface of the charge carrier layer to pass through the thin film form of electrically insulating resin layer due to a tunneling phenomenon for accumulation on the photoconductive or electrically conductive layer, thereby retaining the electrostatic latent image in the recording medium.
However, when the charge carrier layer is merely made up of a resin of high insulating properties, not only is there a problem that the carried charges attenuate with time, but it is also required to keep the electrostatic latent image in store. Problems with patterning the information recording layer are that the process of fabricating the electrostatic information recording medium is complicate, and some limitation is placed on resolution as well, although depending on pixel size.
The present invention has been accomplished so as to provide a solution to the problems mentioned above; it is an object of the invention to provide an electrostatic information recording medium and a method of recording and reproducing electrostatic information, which enable electrostatic information such as an electrostatic latent image to be recorded in the form of a charge trap, rather than an electrostatic charge.